1 files changed, 119 insertions, 0 deletions
diff --git a/thirdparty/thekla_atlas/nvmath/Box.cpp b/thirdparty/thekla_atlas/nvmath/Box.cpp
new file mode 100644
index 0000000000..8f2014a077
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmath/Box.cpp
@@ -0,0 +1,119 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#include "Box.h"
+#include "Box.inl"
+#include "Sphere.h"
+
+using namespace nv;
+
+
+
+
+// Clip the given segment against this box.
+bool Box::clipSegment(const Vector3 & origin, const Vector3 & dir, float * t_near, float * t_far) const {
+
+	// Avoid aliasing.
+	float tnear = *t_near;
+	float tfar = *t_far;
+
+	// clip ray segment to box
+	for (int i = 0; i < 3; i++)
+	{
+		const float pos = origin.component[i] + tfar * dir.component[i];
+		const float dt = tfar - tnear;
+
+		if (dir.component[i] < 0) {
+			
+			// clip end point
+			if (pos < minCorner.component[i]) {
+                tfar = tnear + dt * (origin.component[i] - minCorner.component[i]) / (origin.component[i] - pos);
+			}
+			
+			// clip start point
+			if (origin.component[i] > maxCorner.component[i]) {
+				tnear = tnear + dt * (origin.component[i] - maxCorner.component[i]) / (tfar * dir.component[i]);
+			}
+		}
+		else {
+
+			// clip end point
+			if (pos > maxCorner.component[i]) {
+				tfar = tnear + dt * (maxCorner.component[i] - origin.component[i]) / (pos - origin.component[i]);
+			}
+
+			// clip start point
+			if (origin.component[i] < minCorner.component[i]) {
+				tnear = tnear + dt * (minCorner.component[i] - origin.component[i]) / (tfar * dir.component[i]);
+			}
+		}
+
+		if (tnear > tfar) {
+			// Clipped away.
+			return false;
+		}
+	}
+
+	// Return result.
+	*t_near = tnear;
+	*t_far = tfar;
+	return true;
+}
+
+
+float nv::distanceSquared(const Box &box, const Vector3 &point) {
+    Vector3 closest;
+
+    if (point.x < box.minCorner.x) closest.x = box.minCorner.x;
+    else if (point.x > box.maxCorner.x) closest.x = box.maxCorner.x;
+    else closest.x = point.x;
+
+    if (point.y < box.minCorner.y) closest.y = box.minCorner.y;
+    else if (point.y > box.maxCorner.y) closest.y = box.maxCorner.y;
+    else closest.y = point.y;
+
+    if (point.z < box.minCorner.z) closest.z = box.minCorner.z;
+    else if (point.z > box.maxCorner.z) closest.z = box.maxCorner.z;
+    else closest.z = point.z;
+
+    return lengthSquared(point - closest);
+}
+
+bool nv::overlap(const Box &box, const Sphere &sphere) {
+    return distanceSquared(box, sphere.center) < sphere.radius * sphere.radius;
+}
+
+
+bool nv::intersect(const Box & box, const Vector3 & p, const Vector3 & id, float * t /*= NULL*/) {
+    // Precompute these in ray structure?
+    int sdx = (id.x < 0);
+    int sdy = (id.y < 0);
+    int sdz = (id.z < 0);
+
+    float tmin = (box.corner(  sdx).x - p.x) * id.x;
+    float tmax = (box.corner(1-sdx).x - p.x) * id.x;
+    float tymin = (box.corner(  sdy).y - p.y) * id.y;
+    float tymax = (box.corner(1-sdy).y - p.y) * id.y;
+
+    if ((tmin > tymax) || (tymin > tmax)) 
+        return false;
+
+    if (tymin > tmin) tmin = tymin;
+    if (tymax < tmax) tmax = tymax;
+
+    float tzmin = (box.corner(  sdz).z - p.z) * id.z;
+    float tzmax = (box.corner(1-sdz).z - p.z) * id.z;
+
+    if ((tmin > tzmax) || (tzmin > tmax)) 
+        return false;
+
+    if (tzmin > tmin) tmin = tzmin;
+    if (tzmax < tmax) tmax = tzmax;
+
+    if (tmax < 0) 
+        return false;
+
+    if (t != NULL) *t = tmin;
+
+    return true;
+}
+